Generally, as disclosed in, e.g., Japanese Patent Publication No. 57-41814 and Japanese Patent Laid-Open No. 57-61436, in a moving/guiding apparatus, one shaft is directly connected to a motor (plus a transmission mechanism, such as a screw), and another shaft fixes the motor, and a force is transmitted through a coupling, so that a stage can move within the X-Y plane. For example, the Y stage is directly connected to the feed screw of a fixed motor, and is driven in the Y direction by rotation of the feed screw. An X stage is also driven in the X direction by the feed screw of the fixed motor. Since the X stage is set on the Y stage and moves in the Y direction as well, together with the Y stage, it cannot be directly connected to the feed screw of the motor fixed outside the stage, and a driving force in the X direction is supplied to it through a coupling. In this arrangement, a driving transmission shaft (e.g., a screw) and a motor are fixed (immobile) to each of the two shafts. This is suitable to transmit a force from outside a vacuum container. This arrangement, however, has the following drawbacks.
(1) The rigidity of the coupling is serially applied to the driving system to cause degradation in rigidity.
(2) Since the coupling rigidity changes depending on the position of the stage, the control characteristics change, and a sufficiently high precision and moving speed cannot be obtained.
(3) When the stage moves, an eccentric load is generated on the Y stage to deform it. Accordingly, the static posture precision (pitching) of the X stage is degraded.
(4) When the stage moves, the position of a barycenter of the system within the plane changes. Hence, when the stage is driven, oscillation, such as pitching or yawing, is induced. This also degrades the dynamic posture precision.
To cover the drawbacks of the above arrangement, a stage arrangement disclosed in Japanese Patent Publication No. 60-23941 is proposed. Even in this stage arrangement, the above items (3) and (4) are not improved. Moreover, this stage arrangement contributes little to the thrust of the coil of the driving linear motor. Therefore, the linear motor has a poor efficiency, and a large adverse influence is imposed by, e.g., heat generation.